Jacalin domain-containing protein OsSalT interacts with OsDREB2A and OsNAC1 to impart drought stress tolerance in planta

Abstract

With the changing climatic conditions, drought has become one of the most threatening abiotic stress factors that adversely affect rice cultivation and productivity. Although the involvement of the jacalin domain-containing protein, OsSalT, has been reported in drought and salinity tolerance, its functional mechanism still remains largely unexplored. In this study, expression of the OsSalT gene was found to be positively correlated with the drought tolerance potential with its higher transcript abundance in the tolerant indica rice cultivar, Vandana, and lower abundance in the susceptible cultivar, MTU1010. Moreover, the overexpression of OsSalT gene in rice and its ectopic expression in tobacco significantly improved drought stress tolerance in the transgenic lines. The transgenic lines exhibited significantly improved growth and higher osmolyte accumulation over the wild-type (WT) plants under drought stress. Fascinatingly, the yeast two-hybrid and bimolecular fluorescence complementation (BiFC) analyses confirmed the interaction of OsSalT protein with two interesting transcription factors (TFs), OsNAC1 and OsDREB2A. In silico analysis followed by yeast two-hybrid assay further revealed that the OsSalT protein interacted with the C-terminal domains of both OsDREB2A and OsNAC1 leading to their activation. This triggered the induction of their downstream drought-responsive genes. Together, this study unravelled a novel model for OsSalT-mediated regulation of drought tolerance in plants.